You're welcome.
What is your tank plumbed to? A sump?
You could just buy a large aquarium that would fit under your stand for the refugium. I am not sure what size would be ideal for a fuge, but considering your large water volume, I would think it would be fairly good sized. You could add a sand bed, liverock, and some macroalgae.
I'm not sure about the skimmer. 58g is the largest that I have kept, so I'm not very familiar with skimmers rated for large tanks.